80 Lb Bag Of Concrete Cubic Yard Calculator

Instantly calculate cubic yards, cubic feet, and 80‑lb bag count for your concrete project – free and immediate.

  • Free
  • No sign-up
  • Instant results

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How to use it

  1. Enter length in feet
  2. Enter width in feet
  3. Enter thickness in inches
  4. Click calculate to see cubic yards, cubic feet, and bag count

Enter the length, width and thickness of the slab you’re pouring and the calculator instantly shows three key numbers: total cubic feet, cubic yards, and how many 80‑lb bags you’ll need. Knowing the exact yardage helps you order the right amount of mix, avoiding costly over‑orders or shortfalls that delay the job. The cubic‑feet result is the raw volume; divide by 27 to see cubic yards, the unit most suppliers quote. Then the bag count is simply the cubic‑feet volume divided by 0.6 ft³ per bag, rounded up. Use these figures to plan budget, schedule deliveries, and communicate with your crew. The tool works for patios, driveways, footings, or any flat concrete pour. You can also save the results or print them for on‑site reference, making it easy to verify orders with your supplier.

Pro tips

  • Add 5‑10% extra for waste to avoid running short
  • Round bag count up to the next whole bag; you can’t buy a fraction
  • Order bags in multiples of a full pallet for better pricing
  • Double‑check thickness conversion; 1 in = 0.0833 ft

Real-life examples

  • A homeowner estimating bags for a 10 ft × 12 ft patio 4‑in thick
  • A contractor planning concrete footings for a new deck
  • A landscaper needing volume for a garden path pour

Case study

Sam needed a 12 ft × 8 ft slab 4 in thick for a garage floor. Using the calculator, he saw he required 2.4 cubic yards, which translated to 13 bags. He ordered 13 bags, avoided extra trips, and finished on schedule.

Frequently asked questions

How many 80‑lb bags are needed for a 5 ft × 10 ft slab 3 in thick?
Enter the dimensions; the calculator will show the exact bag count, rounding up to the next whole bag.
Why does the calculator show cubic yards instead of just cubic feet?
Suppliers price concrete by the cubic yard, so the conversion helps you match their quoting units.
Can I use the tool for slopes or uneven surfaces?
The calculator assumes a flat, uniform thickness; for slopes break the area into sections and sum the results.
What if I have a different bag size?
The tool is calibrated for 80‑lb bags (0.6 ft³ each); for other sizes adjust the bag count manually using the volume per bag.
Do I need to account for shrinkage?
Shrinkage is minimal for the mix; the main allowance is waste, so add a small percentage to the bag total.